DP/最短路 URAL 1741 Communication Fiend

题目传送门

/*
    题意：程序从1到n版本升级，正版+正版->正版，正版+盗版->盗版，盗版+盗版->盗版
            正版+破解版->正版，盗版+破解版->盗版
    DP：每种情况考虑一遍，递推就行了
    注意：开long long
*/
#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
#include <cmath>
using namespace std;

const int MAXN = 1e4 + 10;
const int INF = 0x3f3f3f3f;
struct Node
{
    int u, v, w;
    char s[10];
}node[MAXN];
long long dp[MAXN][2];

bool cmp(Node x, Node y)
{
    if (x.u == y.u)    return     x.v < y.v;
    return x.u < y.u;
}

int main(void)        //URAL 1741 Communication Fiend
{
    //freopen ("T.in", "r", stdin);

    int n, m;
    while (scanf ("%d%d", &n, &m) == 2)
    {
        for (int i=1; i<=m; ++i)
        {
            scanf ("%d %d %d %s", &node[i].u, &node[i].v, &node[i].w, &node[i].s);
        }
        sort (node+1, node+1+m, cmp);

        memset (dp, -1, sizeof (dp));
        dp[1][0] = 0;
        for (int i=1; i<=m; ++i)
        {
            Node a = node[i];
            if (a.s[0] == 'L')
            {
                if (dp[a.u][0] != -1 && (dp[a.v][0] == -1 || dp[a.v][0] > dp[a.u][0] + a.w))
                {
                    dp[a.v][0] = dp[a.u][0] + a.w;
                }
            }
            else if (a.s[0] == 'P')
            {
                if (dp[a.u][0] != -1 && (dp[a.v][1] == -1 || dp[a.v][1] > dp[a.u][0] + a.w))
                {
                    dp[a.v][1] = dp[a.u][0] + a.w;
                }
                if (dp[a.u][1] != -1 && (dp[a.v][1] == -1 || dp[a.v][1] > dp[a.u][1] + a.w))
                {
                    dp[a.v][1] = dp[a.u][1] + a.w;
                }
            }
            else if (a.s[0] == 'C')
            {
                if (dp[a.u][0] != -1 && (dp[a.v][0] == -1 || dp[a.v][0] > dp[a.u][0] + a.w))
                {
                    dp[a.v][0] = dp[a.u][0] + a.w;
                }
                if (dp[a.u][1] != -1 && (dp[a.v][1] == -1 || dp[a.v][1] > dp[a.u][1] + a.w))
                {
                    dp[a.v][1] = dp[a.u][1] + a.w;
                }
            }
        }

        if (dp[n][0] == -1 && dp[n][1] == -1)    puts ("Offline");
        else
        {
            puts ("Online");
            if (dp[n][0] == -1)    printf ("%I64d
", dp[n][1]);
            else if (dp[n][1] == -1)    printf ("%I64d
", dp[n][0]);
            else    printf ("%I64d
", min (dp[n][0], dp[n][1]));
        }
    }

    return 0;
}

/*
Online
Offline
*/

/*
    WA了4，5发，第一是抄Kuangbin的模板抄错了；第二是选取的INF值太小了
    以后学习一下最值的选取的方法:)
*/
#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
#include <vector>
#include <cmath>
#include <queue>
using namespace std;

const int MAXN = 1e4 + 10;
const int INF = 0x3f3f3f3f;
const int INFF = 0x7fffffff;
const long long inf = ((long long)1<<50);
struct Edge
{
    int v, w;
    int f;
    Edge (int _v = 0, int _w = 0, int _f = 0) : v (_v), w (_w), f (_f) {}
};
bool vis[MAXN];
int cnt[MAXN];
long long d[MAXN][2];
vector<Edge> G[MAXN];
int n, m;

void add_edge(int u, int v, int w, int f)
{
    G[u].push_back (Edge (v, w, f));
}

bool SPFA(int s)
{
    memset (cnt, 0, sizeof (cnt));
    memset (vis, false, sizeof (vis));
    for (int i=1; i<=n; ++i)    d[i][0] = d[i][1] = inf;
    vis[s] = true;    d[s][0] = 0;    cnt[s] = 1;

    queue<int> Q;    Q.push (s);
    while (!Q.empty ())
    {
        int u = Q.front ();    Q.pop ();
        vis[u] = false;                        //失误！
        for (int i=0; i<G[u].size (); ++i)
        {
            int v = G[u][i].v;    int w = G[u][i].w;    int f = G[u][i].f;
            if (f == 0)
            {
                if (d[v][0] > d[u][0] + w)    d[v][0] = d[u][0] + w;
            }
            else if (f == 1)
            {
                if (d[v][1] > d[u][0] + w)    d[v][1] = d[u][0] + w;
                if (d[v][1] > d[u][1] + w)    d[v][1] = d[u][1] + w;
            }
            else
            {
                if (d[v][0] > d[u][0] + w)    d[v][0] = d[u][0] + w;
                if (d[v][1] > d[u][1] + w)    d[v][1] = d[u][1] + w;
            }
            if (!vis[v])
            {
                vis[v] = true;    Q.push (v);
                if (++cnt[v] > n)    return true;
            }
        }
    }

    return false;
}

int main(void)        //URAL 1741 Communication Fiend
{
    //freopen ("T.in", "r", stdin);

    while (scanf ("%d%d", &n, &m) == 2)
    {
        for (int i=1; i<=n; ++i)    G[i].clear ();
        for (int i=1; i<=m; ++i)
        {
            int u, v, w, f;    char s[10];
            scanf ("%d %d %d %s", &u, &v, &w, &s);
            if (s[0] == 'L')    f = 0;
            else if (s[0] == 'P')    f = 1;
            else if (s[0] == 'C')    f = -1;
            add_edge (u, v, w, f);
        }

        if (!SPFA (1))
        {
            long long ans = min (d[n][0], d[n][1]);
            if (ans == inf)    puts ("Offline");
            else    {puts ("Online");    printf ("%I64d
", ans);}
        }
    }

    return 0;
}

/*
Online
Offline
*/